Manufacture of wrought iron



1,469,373? ATENY rice.

JAMES ASTON, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOB TO A. M. BYERS COM- ?.ANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

MANUFACTURE OF WROUGHT IRON.

No Drawing. Application filed June 8, 1921, Serial No. 476,020. Renewed November 24, 1922.

To all whom it may concern:

Be it known that I, JAMES AsroN, a citizen of the United States, residing at Pittsburgh in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in the Manufacture of Wrought Iron, of which the following is a full, clear, and exact description.

My invention relates to the process of making wrought iron wherein the product of a steel making process is poured into a bath of slag having puddling characteristics to granulate the metal and form a coherent mass of slag and metal, as described in my co-pending applications Serial No. 376,247, filed April 24, 1920,.for methods of making wrought iron, and Serial No. 376,388, filed April 24, 1920, for processes of making;

wrought iron;

29 In carrying out this process, I have found that as the molten metal is poured into the molten slag the temperature of the slag is raised by the molten metal so that the temperature of the molten slag is liable to rise to or above the melting point of the metal. In casethe temperature of the slag bath is allowed to rise, it is liable to reach a range of temperature in which the metal is not properly comminuted or anulated, thus causing imperfect and insu cient slag distribution and even the presence of molten metahwhich will injure the product.

I have discovered that this rise into the danger zone of temperature may be avoided either by providing a sufliciently large volume of slag relative to the amount of metal poured in, or by cooling the bath during the introductionof the molten metal, as for instance by feeding in'cold pulverized slag or cold eomminuted metal. I may use either or both of these ways of preventing the temperature from rising'into the danger zone.

The temperature of the product of the steel-making operation may be assumed as being from 2800 to 2900 F. It solidifies at about 2730 F. The slag temperature of an ordinary puddle slag in molten condition is about 2200 to 2300 F. In order to provide for proper welding of the granules in the slag bath to form the mixed coherent mass of slag and metal, a temperature is desired of about 2500 to 2600 F; but the temperature should not rise beyond the .fusion point of the metal, which, as above stated, is about 2730 F., and is preferably kept Well below this latter temperature. 1th a fixed quantity of molten slag, as

more' and more metal is poured into it the p, equlllbrium temperature will rise until, if

ably over 2 to 1. In fact, for complete safety by relative volumes alone, the slag volume may well be increased to 3 volumes of slag to 1 of metal. (Relative weights of 1% to 1). I

But if cold pulverized slag is added to the'slag bath during the pouring in of the molten metal, the initial volume of slag relative to metal may, of course be less.

If: one volume of slag is used to one volume of metal, cold slag additions should be made to an amount of at least 6% by weight of slag addition relative to the amount of metal poured in, and the cold addition is preferably carried above this percentage to obtain the desired result. For example,

'with a slag metal ratio of 2 volumes to 1,

where the initial temperature of the slag is about 2300 F. and the temperature of the metal about 2900 F., I have added cold pulverized slag in successive small amounts to approximately 12 per cent by weight of metal poured in, wit-h good results.

I have also found that the greater the temperature difierence which is maintained between the slag bath and the metal, the more efl'ective is the granulating action. It is, therefore, desirable to keep the temperature difference well away from the danger zone, not onl to insure granulating, but to produce e cient thorough granulating. In any case, the final equilibrium temperature of the bath, after the pouring in of the molten metal is completed, should be below the melting point of the metal; and this may be insured either by a suflieiently large volume of slag relative to metal, or

day cold additions, or by both.

till

As in my copending applications above referred to, the temperatures,'speed of introduction of the metal, amount of cold addi-- tions, it used, etc., should be so regulated that the equilibrium of temperature is within the welding range so that the mass of mixed metal and slag will weld together and form a coherent mass as the granules descend through the bath to the lower part of the receptacle or vessel containing the bath.

After the operation, the surplus slag may be removed and the mass or ball compressed either in the same receptacle or after removal therefrom.

'Iheadvantages ofmy invention will be,

obvious to those skilled in the art, since thorough and uniform slag distribution is insured, and large slagless lumps or masses of metal avoided, as is also the presenceof molten metal in the bath. For the production of high grade wrought iron, therefore, this invention is highly important, as it insures thorough granulating and very uniform slag distribution. Changes may be made in the particular slag used, although this should be of general puddling "characteristics, and in the character of the molten the metal to granulate it therein, and keepin the temperature of the molten slag bath M ow the melting point of the metal throughout the operation.

3. In the manufacture of wrought iron, the steps consisting of subjecting metal to a steel-making operation, pouring the prodnot into molten slag of a lower temperature than the metal to granulate it therein, and keeping the temperature of the molten slag bath below the melting point of the metal throughout the operation by artificially cooling the bath.

t. In the manufacture of wrought iron, the steps consisting of subjecting metal to a steel-making operation, pouring the product into molten slag of a lower temperature than the metal to granulate it therein, and keeping the temperature at the molten slag bath rename below the melting point of the metal throughout the operation by making cold additions to the bath.

5. In the manufacture of wrought iron, the steps consisting of subjecting metal to a steel-making operation, pouring the-product into molten slag of a lower temperature than the metal to granulate it therein, and keeping the temperature of the molten slag bath below the melting point of the metal throughout the operation I making additions of cold slag to the; bath;

6. In the manufacture of wrought iron,

the steps consisting of subjecting metal to a steel-making operation, pouring the product into molten slag of a lower temperature than the metal to granulate it therein, and keeping the temperature of the molten slag bath below the melting point of the metal throughout the'operation by using a larger volume of slag than-the amount of metal poured in.

7. In the manufacture of wrought iron, the steps consisting ofsubjecting metal to a steel-making operation, pouring the product into molten slag of a lower temperature than the metal to granulate it therein, and keeping the temperature of the molten slag bath below the melting point of the metal throughout the operation by using a larger volume of slag than the amount of metal poured in and making cold additions thereto;

8. In the manufacture of wrought iron, the steps consisting of subjecting metal to a steel-making operation, pouring the product into molten slag of a lower temperature than the metal to granulate it therein, and keeping the temperature of the molten slag bath below the melting point of the metal throughout the operation by using a volume ratio of at least 1% of slag to I of metal.

9. In the manufacture of wrought iron, the steps consisting of subjecting metal to a steel-making operationQpouring the product into molten slag ofa lower temperature than the metal to granulate it therein, and keeping the temperature of the molten slag bath below the melting point of the metal throughout'the operation by using a :volume ratio of at least 14,; of slag to 1 of metal and making cold additions.

10. In the manufacture of wrought iron,

the steps consisting of granulating the inch.

ten product of the steel-making operation, mixing the granules while retaining at least a part off-their original heat with a'slag of paddling characteristics, and maintaining the temperature of the molten slag below the melting point of the metal through the mixing operation.

In testimony whereof, I have hereunto set my hand.

t JAMES ASTON. 

